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Author Topic: What is the basis of the Davisson and Germer experiment?  (Read 1623 times)

Offline theCoolScientist

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during the experiment diavisson and germer observed normal readings(nothing unusual),then their nickel target got oxidised ,then they decided to anneal it.After annealing they got the famous result we all studied.What did annealing change about the nickel crystal?how?in brief
« Last Edit: 06/12/2014 00:19:36 by chris »


 

Offline alancalverd

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Re: davisson and germer experiment
« Reply #1 on: 03/12/2014 05:48:16 »
Don't know the answer right away but it's a commonly observed fact that many discharge systems (e.g. gas lasers, fluorescent tubes...) don't work properly until they have acquired a certain amount of "gunge".
 

Offline evan_au

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Re: davisson and germer experiment
« Reply #2 on: 03/12/2014 08:07:30 »
Electron diffraction, such as demonstrated by the Davisson–Germer experiment is very similar to X-Ray diffraction (of which we are celebrating the centenary this year).

Both techniques work better, and give a clearer diffraction pattern if the target is a single crystal.
The annealing step converted polycrystalline nickel into large crystals, which then gave a clear diffraction pattern when the electron wavelength was similar to the spacing of nickel atoms.

Forming a single crystal of organic substances is one of the major barriers to X-Ray crystallography - sometimes a researcher can spend years and still fail to create a single crystal of a large protein. Fortunately, nickel forms large crystals fairly readily (eg by annealing).
 

Offline PmbPhy

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Re: What is the basis of the Davisson and Germer experiment?
« Reply #3 on: 06/12/2014 21:13:41 »
during the experiment diavisson and germer observed normal readings(nothing unusual),then their nickel target got oxidised ,then they decided to anneal it.After annealing they got the famous result we all studied.What did annealing change about the nickel crystal?how?in brief
I would assume that annealing reversed the oxidation. Wouldn't that be the case?
 

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Re: What is the basis of the Davisson and Germer experiment?
« Reply #3 on: 06/12/2014 21:13:41 »

 

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